Passing data from AlertDialog to same screen - flutter

Question

I'm having some trouble simply sending data from AlertDialog to our mainscreen that is _MyHomePageState and into the defined Text widget saying "Paste here!".
I also have a few questions regarding passing data in this scenario (where we are sending data from pop up window to same or other screen):
1.) Is using AlertDialog widget in this scenario even the correct technique?
2.) What's the correct method when passing input data and displaying it, do we first save it into an array and then retrieve value from array? Do we use stack or some other array method?
3.) Why or why not should I put my logic into the _MyHomePage class or it doesn't matter?
4.) Should I use custom component that I call from some other file for pop up button/window? (feels like there's just a bunch of stuff code wise that could be elsewhere on its own in its own file)
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
GlobalKey<FormState> _formKey = GlobalKey<FormState>();
Future<void> showInformationDialog(BuildContext context) async {
return await showDialog(context: context,
builder: (context) {
final TextEditingController _textEditingController = TextEditingController();
bool isChecked = false;
final TextEditingController _testEE = TextEditingController();
return StatefulBuilder(builder: (context, setState) {
return AlertDialog(
content: Form(
key: _formKey,
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
TextFormField(
controller: _testEE,
validator: (value) {
//check if value is empty
return value.isNotEmpty ? null : "Invalid Field";
},
decoration: InputDecoration(hintText: "Enter text"),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text("Choice"),
Checkbox(value: isChecked, onChanged: (checked) {
setState((){
isChecked = checked;
});
})
],
)
],
)),
actions: <Widget>[
TextButton(
child: Text("Okay"),
onPressed: () {
var _test = _testEE.text;
print("test?" + _test);
if(_formKey.currentState.validate()) {
Navigator.of(context).pop();
}
},
)
],
);
});
});
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.teal[800],
body: ListView(
children: <Widget>[
Padding(
padding: EdgeInsets.only(top: 15.0, left: 40.0),
child: Row(
children: <Widget>[
Text('Check List',
style: TextStyle(
fontFamily: 'Montserrat',
color: Colors.white,
fontWeight: FontWeight.bold,
fontSize: 25.0)),
IconButton(
padding: EdgeInsets.only(left: 140.0),
icon: Icon(Icons.menu),
color: Colors.white,
onPressed: () {},
)
],
),
),
SizedBox(height: 15.0),
Container(
height: MediaQuery.of(context).size.height - 100.0,
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(topLeft: Radius.circular(75.0)),
),
child: ListView(
primary: false,
padding: EdgeInsets.only(left: 35.0, right: 35.0),
children: <Widget>[
Padding(
padding: EdgeInsets.only(top: 25.0),
child: Container(
height: MediaQuery.of(context).size.height - 300.0,
child: ListView(children: [
Padding(
padding: const EdgeInsets.only(top: 5.0),
child: Text('Test 1',
style: TextStyle(
fontFamily: 'Montserrat',
color: Colors.black,
fontWeight: FontWeight.bold,
fontSize: 15.0)),
),
Padding(
padding: const EdgeInsets.only(top: 5.0),
child: Text("Paste here!",
style: TextStyle(
fontFamily: 'Montserrat',
color: Colors.black,
fontWeight: FontWeight.bold,
fontSize: 15.0)),
),
//_buildFoodItem('assets/plate5.png', 'Berry bowl', '\$24.00')
]))),
//Button Row
Padding(
padding: const EdgeInsets.only(top: 60.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
SizedBox(
width: 75.0,
height: 75.0,
child: ElevatedButton(
onPressed: () async {
await showInformationDialog(context);
},
child: Text("Add"),
style: ElevatedButton.styleFrom(
side: BorderSide(width: 2.0, color: Colors.black),
shape: CircleBorder(),
padding: EdgeInsets.all(20),
primary: Colors.white, // <-- button color
onPrimary: Colors.black, // <-- splash color
),
),
),

Answer 1

Returning a parameter from a pushed screen or dialog is simple.
The method pop() you used accepts a optional result parameter:
Navigator.pop(context, _test); // _test will be returned
The documentation of this method can be read here.
Use this to return the previous screen the value you want. You need to use await and keep the result in a variable:
onPressed: () async {
String result = await showInformationDialog(context);
setState((){
myText=result;
});
},
Remember to declare myText inside your State class:
class _MyHomePageState extends State<MyHomePage> {
String myText = ''; // add this.
And use this variable where you need it:
[...]
child: Text(myText,
[...]
You can read more about it in this cookbook from Flutter team.
Ps: About the other questions, most of them are opinion based. They are project decisions and each have pros and cons. I believe that if this is a simple project it won't matter so much. If you need to dive deeper in these topics I suggest you to create other questions, since they are unrelated to this one.